<table border="1" class="dataframe">
  <thead>
    <tr style="text-align: right;">
      <th></th>
      <th></th>
      <th></th>
      <th>n</th>
    </tr>
    <tr>
      <th>a</th>
      <th>b</th>
      <th>c</th>
      <th></th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <th rowspan="21" valign="top">100</th>
      <th rowspan="7" valign="top">10</th>
      <th>1</th>
      <td>0</td>
    </tr>
    <tr>
      <th>2</th>
      <td>1</td>
    </tr>
    <tr>
      <th>3</th>
      <td>2</td>
    </tr>
    <tr>
      <th>4</th>
      <td>3</td>
    </tr>
    <tr>
      <th>5</th>
      <td>4</td>
    </tr>
    <tr>
      <th>6</th>
      <td>5</td>
    </tr>
    <tr>
      <th>7</th>
      <td>6</td>
    </tr>
    <tr>
      <th rowspan="7" valign="top">20</th>
      <th>1</th>
      <td>7</td>
    </tr>
    <tr>
      <th>2</th>
      <td>8</td>
    </tr>
    <tr>
      <th>3</th>
      <td>9</td>
    </tr>
    <tr>
      <th>4</th>
      <td>10</td>
    </tr>
    <tr>
      <th>5</th>
      <td>11</td>
    </tr>
    <tr>
      <th>6</th>
      <td>12</td>
    </tr>
    <tr>
      <th>7</th>
      <td>13</td>
    </tr>
    <tr>
      <th rowspan="7" valign="top">30</th>
      <th>1</th>
      <td>14</td>
    </tr>
    <tr>
      <th>2</th>
      <td>15</td>
    </tr>
    <tr>
      <th>3</th>
      <td>16</td>
    </tr>
    <tr>
      <th>4</th>
      <td>17</td>
    </tr>
    <tr>
      <th>5</th>
      <td>18</td>
    </tr>
    <tr>
      <th>6</th>
      <td>19</td>
    </tr>
    <tr>
      <th>7</th>
      <td>20</td>
    </tr>
    <tr>
      <th rowspan="19" valign="top">200</th>
      <th rowspan="7" valign="top">10</th>
      <th>1</th>
      <td>21</td>
    </tr>
    <tr>
      <th>2</th>
      <td>22</td>
    </tr>
    <tr>
      <th>3</th>
      <td>23</td>
    </tr>
    <tr>
      <th>4</th>
      <td>24</td>
    </tr>
    <tr>
      <th>5</th>
      <td>25</td>
    </tr>
    <tr>
      <th>6</th>
      <td>26</td>
    </tr>
    <tr>
      <th>7</th>
      <td>27</td>
    </tr>
    <tr>
      <th rowspan="5" valign="top">20</th>
      <th>1</th>
      <td>28</td>
    </tr>
    <tr>
      <th>2</th>
      <td>29</td>
    </tr>
    <tr>
      <th>...</th>
      <td>...</td>
    </tr>
    <tr>
      <th>6</th>
      <td>33</td>
    </tr>
    <tr>
      <th>7</th>
      <td>34</td>
    </tr>
    <tr>
      <th rowspan="7" valign="top">30</th>
      <th>1</th>
      <td>35</td>
    </tr>
    <tr>
      <th>2</th>
      <td>36</td>
    </tr>
    <tr>
      <th>3</th>
      <td>37</td>
    </tr>
    <tr>
      <th>4</th>
      <td>38</td>
    </tr>
    <tr>
      <th>5</th>
      <td>39</td>
    </tr>
    <tr>
      <th>6</th>
      <td>40</td>
    </tr>
    <tr>
      <th>7</th>
      <td>41</td>
    </tr>
    <tr>
      <th rowspan="21" valign="top">300</th>
      <th rowspan="7" valign="top">10</th>
      <th>1</th>
      <td>42</td>
    </tr>
    <tr>
      <th>2</th>
      <td>43</td>
    </tr>
    <tr>
      <th>3</th>
      <td>44</td>
    </tr>
    <tr>
      <th>4</th>
      <td>45</td>
    </tr>
    <tr>
      <th>5</th>
      <td>46</td>
    </tr>
    <tr>
      <th>6</th>
      <td>47</td>
    </tr>
    <tr>
      <th>7</th>
      <td>48</td>
    </tr>
    <tr>
      <th rowspan="7" valign="top">20</th>
      <th>1</th>
      <td>49</td>
    </tr>
    <tr>
      <th>2</th>
      <td>50</td>
    </tr>
    <tr>
      <th>3</th>
      <td>51</td>
    </tr>
    <tr>
      <th>4</th>
      <td>52</td>
    </tr>
    <tr>
      <th>5</th>
      <td>53</td>
    </tr>
    <tr>
      <th>6</th>
      <td>54</td>
    </tr>
    <tr>
      <th>7</th>
      <td>55</td>
    </tr>
    <tr>
      <th rowspan="7" valign="top">30</th>
      <th>1</th>
      <td>56</td>
    </tr>
    <tr>
      <th>2</th>
      <td>57</td>
    </tr>
    <tr>
      <th>3</th>
      <td>58</td>
    </tr>
    <tr>
      <th>4</th>
      <td>59</td>
    </tr>
    <tr>
      <th>5</th>
      <td>60</td>
    </tr>
    <tr>
      <th>6</th>
      <td>61</td>
    </tr>
    <tr>
      <th>7</th>
      <td>62</td>
    </tr>
  </tbody>
</table>
